William M. Vollmer

Although asthma is on the rise in the United States and elsewhere, data on age–sex-specific patterns of change in various types of health care utilization are scarce. We report on 20-yr trends in the treated prevalence of asthma among members of a large health maintenance organization. Data are presented separately for each of six age–sex categories, and include both the treated prevalence of asthma as well as the treated prevalence of the broader category of chronic airflow obstruction (CAO), defined as asthma, chronic bronchitis, or emphysema. During the period 1967–1987 the treated prevalence of asthma and CAO increased significantly in all age–sex categories except males aged 65 and older. These patterns are in contrast to previous studies of this population that showed that increases in asthma hospitalizations and hospital-based episodes of care were limited primarily to young boys. Not only do these findings support other evidence of a real increase in asthma prevalence, but they also highlight the risks associated with drawing inferences about changing disease epidemiology based on a single type of health care utilization.

The Dietary Approaches to Stop Hypertension (DASH) study was a National Heart, Lung, and Blood Institute multicenter trial that compared the impact of three dietary patterns on blood pressure (BP) among adults with high normal blood pressure or mild (Stage I) hypertension. DASH's high minority representation (two-thirds of the 459 randomized participants came from minority populations, and 60% of the cohort were African American) offered a valuable opportunity to assess factors affecting minority enrollment and retention in clinical trials of lifestyle modification. Recruitment strategies included targeted mailings to specific groups, mass mailings, community and worksite screenings, and mass media advertising; the four DASH clinical centers also reimbursed participants from $150 to $160. The most productive recruitment strategies tended to be mass mailings directed at a broad audience that was weighted toward, but not limited to, minority participants. DASH's African-American participants overwhelmingly (89%) cited health and dietary factors, such as learning more about blood pressure and healthy eating habits, as their primary reason for participating, while only six percent listed the financial incentives as their primary reason for participating. Eighty-eight percent of African-American respondents reported they would participate again in a similar study. The insights from DASH should help inform future efforts to recruit minority participants.

T.J. Moore, L.P. Svetskey, L.J. Appel, W.M. Vollmer, D. Simons-Morton, D. Harsha, F.M. Sacks; The effect of dietary patterns on ambulatory blood pressure (ABP)